DMM sees GHOST Voltages

[Antonius]

Hello I have an old DMM from Siemens B1002, the open circuit probe AC Voltage values after switching ON randomly begin high in hundreds 700ish, 1074, 666, 240... then it very slowly counts down, and a bit up again (very weird) hanging around at ~14 Volts, 48, 21, etc., never reaching 000. Why is the DMM doing this? I have changed the Battery to a fully charged 9V Battery.

[goaty]

- Does it behave different in DC voltage ?
- Short the leads, does it change ?
- Measure with another meter the input impedance in DC should be 10MOhm.
- Maby the rectifier circuit around the TL066 is damaged. Check the 1N4148 and caps.
- Also clean any dirt on high impedance circuitry. There is 22MOhm feedback resistor around TL066.